how to validate a usercontrol when it is added dynamically

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C#

i have added a usercontrol dynamically by this code to a panel

int c = 0;
private void button1_Click(object sender, EventArgs e)
{
  int v;
  v = c++;
  panel1.VerticalScroll.Value = VerticalScroll.Minimum;

  UserControl1 us = new UserControl1();
  us.Name = "us" + v;
  us.Location = new Point(150, 5 + (30 * v));
  us.Tag = btn;
  panel1.Controls.Add(us);
}

i have a two button on the form one for making the dynamic usercontrol and one for passing the text to other form, before passing it to another form i want to validate the text and cancle the process of transferring the text if any control in the usercontrol is left blank,the control in the usercontrol is comboboxes and textbox, so i have writte this method

UserControl1 uss = new UserControl1();
public bool validation()
{
  if (uss.comboBox1.Text == string.Empty)
  {
     return true;
  }
  else
  {
     return false;
  }
}

and the below code is at the validating button

bool vss = validation();
if (!vss)
{
  errorlabel.Visible = false;   //this label is defaultly set to false
  Form4 fl = new Form4(); 
  fl.Show();
}
else
{
 errorlabel.Visible = true;    //this label is defaultly set to false
}
//but the validation is not done properly, whats the problem here